Omnipositional rotary switch



April 11, 1961 D. CURTIS OMNIPOSITIONAL ROTARY SWITCH 2 Sheets-Sheet 1 Filed Oct. 30, 1958 United States Patent OMNIPOSITIONAL ROTARY swrrcn Daniel L. Curtis, Manhattan Beach, Calif., assignor, by mesne assignments, to Litton Systems, Inc., Beverly Hills, Calif., a corporation of Maryland Filed Oct. 30, 1958, Ser. No. 770,724

12 Claims. (Cl. 200-32) This invention relates to liquid jet rotary switches and more particularly to an omnipositional switch having a rotor element that provides a positive pumping of expelled liquid from the jet exit to a reservoir.

In prior art rotary jet switches, the return path of the expended conductive liquid is controlled only in the most general fashion. The liquid jet is initially directed at contacts with appreciable velocity and, by deflecting the liquid stream, the force of gravity and a high volume flow of liquid are sufficient to return the liquid to a reservoir. Switches that have been designed to operate in all positions usually include intricate duct configurations, impeller vanes, slinger disks, and the other elaborate arrangements to return the liquid to the reservoir from the jet exit, without the aid of gravity. However, prior art switches all provide an area of free fall and rely on the velocity and volume of flow of liquid to carry the liquid to the return path.

As the jet strikes the contacts at high velocities, the liquid splashes and splatters and the area in the switch between the jet exit and the fiuid return elements is quickly filled with a cloud containing vapor, fog, and even droplets of the conducting liquid. In equilibrium operation, however, the volume of liquid pumped through the jet orifice is sufiicient to assure a return liquid flow that sustains the operation.

In low-level analog signal circuits, prior art liquid jet rotary switches have been unsatisfactory for many reasons, some of which are suspected to be attributable to the presence of the aforementioned cloud in the switch. In operation, these switches exhibit a background current of several microamperes possibly due to a static charge developing in the cloud. Random cross currents have also been found to develop between contacts, possibly due to conduction through the cloud. A third shortcoming is the presence of random noise signals which, in addition to the background currents and cross currents, may also be due to charged droplets of liquid sporadically impinging on a contact.

In low-level analog signal switching, currents representing'the magnitude of a quantity are usually in the milliampere and even the microampere range. Random noise signals of that order of magnitude are easily confused with changes in a measured quantity and obviously cannot be tolerated.

According to the present invention, a conductive liquid, preferably mercury, is utilized in a rotary switch of novel design. A motor driven rotor including a disk portion is mounted in a housing. The configuration of the opposing rotor and housing surfaces is such to result in a positive pumping action on expelled fluid, forcing the fluid from the jet orifice to the reservoir. As a result, the liquid flow is controlled at all times 'and at all points in the flow loop.

The rotor disk is of a conductive material, which, due

to its proximity to the area in which the cloud forms, tends to bleed off any static charge from suspended particles. A band of a non-conductive material is placed e 2,979,578 Patented Apr. 11, 1961 2 V on the rotor disk periphery to prevent undesired electrical connection between'the rotor and contacts other than those to which the jet is directed.

The disk has a jet orifice in its periphery which is in fluid communication with the reservoir and a pumping element, afiixed to the rotor, transports liquid from the reservoir to the orifice through a channel internal to the rotor. The opposite faces of the disk having unequal areas, the face on the side of the reservoir having the greater circumference. As a result, the peripheral rim of the disk has a taper or bevel from the smaller to the larger face; The shape of the adjacent inner surface is complementary to that of the disk and is closely spaced therefrom. During rotation, a force is exerted on expelled liquid, positively driving it toward the reservoir through the opening between the disk and the adjacent inner surface.

In a specific embodiment, as a commutator, an array of contacts are circumferentially disposed about the ad jacent inner surface of the switch housing in the locus of the jet orifice. -In operation, a plurality of circuits are sequentially connected to a single circuit. j

Interposed between the reservoir and the face of the rotor disk is a baffle plate. The plate is provided to keep the liquid from the face of the disk when revolving, thereby reducing viscous drag. When in operation, any liquid that does get past the bafile is quickly picked up and pumped out by the centrifugal force imparted to the liquid by the rotating disk. The baffle also electrically connects the mercury to the single circuit. Because of the positive force exerted upon the liquid at all times, the force of gravity is not needed in the flow path and the switch can be operated in any position.

In a second embodiment, a double row of contacts is disposed around the inner surface of the switch. In operation, the liquid jet bridges a gap between each pair of contacts that are connected to the same circuit, thereby completing the electrical connection of each circuit, in order.

The inner surface of the switch, the rotor disk, and thev non-conductive band are preferably composed of materials that are not wetted by mercury. On the other hand, the electrical contacts which connect toterminals on the exterior of the switch, should be of a material that is wetted by the mercury, thereby assuring a better electrical connection.

Accordingly, it is an object of the invention to provide a high speed, omnipositional liquid jet contactor in which conductive liquid is positively pumped throughout the entire flow loop;

It is a further object of the invention to provide a high speed liquid jet contactor having a conductive rotor to bleed off static charges; 7

It is a still further object of the invention to provide a rotor for a liquid jet rotary switch, having a tapered peripheral surface which cooperates with a tapered inner wall of the switch to positively direct the flow of liquid trapped therebetween;

It is a further object of the invention to provide a llquid jet rotary switch having a conductive rotor with a non-conductive peripheral band for preventing accidental electrical connection through the rotor to non-selected contacts;

It is an additional object of the invention to provide in an omnipositional high speed rotary jet commutator, a baffle plate interposed between the reservoir of conductive liquid and the rotor for electrically connecting the liquid to a common circuit;

It is an additional object of the invention to provide in an omnipositional high speed rotary jet commutator, a baffle plate interposed between the reservoir of conductive liquid and the rotor for electrically connecting the liquid gamers E p to a common circuit and for diminishing the viscous drag on the rotor by the liquid in the reservoir;

It is a further object of the invention to provide in a high speed mercury jet contactor, a rotor that assures.

positive unidirectional liquid flow from thejet exit to the reservoir;

It isa still further object. of the invention toprovide an improved. mercury jet commutator in which static charge on expended mercury is bled oif by a conductive rotor.

The novel features which are believed to be characteristicof the invention, both as to its organization and method of operation, together with further objects and advanages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which several embodiments of the invention are illustrated by way of example. it is to be expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention.

Figure l is a side sectional view, of an omnipositional high speed rotary switch of the present invention;

Figure 2 is a top sectional view of the apparatus of Figure 1 taken alongthe line 2-2 in the direction of the appended arrows;

Figure 3 is a side sectional view of a portion of the rotor disk and housing wall of Figure l and,

Figure 4 is a side sectional view ofa portion of a different switch housing showing an alternate placement of conductors.

With reference now to Figure 1, there is shown a high speed omnipositional rotary switch according to the present invention embodied in a mercury jet commutator. A motor This connected to a drive shaft 12 journalled in a sealed bearing 14 which is fastened to a commutator housing 16. The portion of the drive shaft 12 within the housing 16 widens into a rotor disk 13. A spindle 2t), coaxial with the drive shaft l2, projects from the rotor disk 18 and is supported in an end bearing 22, also in the commutator housing in. A plurality of contact wires 24, each of which terminates at a contact 26, arrayed about the inner surface 28 and are brought out to a corresponding array of terminals 39, disposed around the housing A bafi'le plate 32 is positioned within the commutator housing 1 6, between a reservoir portion 34 and one face 32', of the rotor disk 18. The baffle plate 32 is of a conductive material and at its junction with the commutator housing 16, a conductive lead is brought out which is adapted to be connected. to a source of common reference potential.

The drive shaft 12 includes a centrifugal pumping sys tem which has a simple scoop vane 33 as shown in Figure 1 between the sealed bearing 14 and the rotor disk 15, located in the reservoir portion 34 of the housing 16; The reservoir contains a conductive liquid, here mercury 44 A filler plug (not shown) is used to add liquid mercury 45) to the reservoir 34. Enough mercury 40 is in the reservoir 34 to assure an uninterrupted jet during high speed operation. A central channel 42, internal to the rotor along the axis of the shaft 12, carries the mercury 46 to the disk 18. An outlet channel 44 within the disk 18 extends radially from the axial line and terminates in a constricted orifice E6 at the periphery 43. It will be readily understood that as the scoop vane 38 on the rotor rotates through the mercury, the inertia of liquid at rest will force mercury into the central channel 42 and thence to the outlet channel 4-4. During rotation, the centrifugal force on the liquid in the outlet channel 44 hurls the mercury toward the periphery of the disk, creating a lower pressure in the central channel 42. The pressure differential in the central channel 42 between the outlet channel 44 and the mercury being captured by the scoop 38 results in a net flow of mercury into the central channel 42. The array of contacts 26 disposed about the inner surface 28 of the commutator housing 46 is concentric with and in the plane of the rotational locus of the orifice 46.

The inner wall surface 28 of the commutator housing 16 is formed to maintain a substantially uniform spacing between the disk periphery 48 and the adjacent inner wall surface 28. The spacing is effectively a mercury return channel in which the mercury can only flow in one direction, toward the reservoir 34. The baffle plate 32 keeps the mercury 40 from the face 36 of the rotor disk 18. In the present embodiment, the baffle 32 also completes the electrical contact between the source of common reference potential and the mercury 40. A nonconductive band 49 (shown in Figure 3) around the periphery of the rotor disk prevents a circuit through the rotor periphery and any contact where mercury might accumulate.

For operation as a commutator, the motor 10 is energized and the shaft 12 rotates. The centrifugal pumping system pumps mercury 44 from the reservoir 34, through the central channel 42, and into the radial outlet channel" 4.4. The spinning of the rotor disk 18 adds a component of pressure due to centrifugal force on the mercury 40, expelling it through the restricted orifice 46 at a high speed.

The stream or jet of mercury 40 sequentially contactseach of the inner contacts 26. During the time interval that the jet is in contact with any contact 26, a low impedance electrical circuit is completed between the common source and whatever external circuit is connected to the terminal 34), associated with the contact 26. The external circuit (not shown) may include a transducer and an input to a device utilizing the transducer output. Alternatively, many terminals 36 may be connected to=a single circuit for multiple signal transmissions in a revolution.

Expended mercury 49, remaining in the area between the rotor periphery 43 and inner wall surface 28 after the stream has rotated away, is quickly pumped back to the reservoir 34 by action of the rotating disk 18; The mercury expelled by the orifice 46 is swept up by the periphery 48 of the rotor disk 13 and is propelled-by centrifugal force through the mercury return. channel formed by the periphery 43 and inner wall 28 toward the outermost edge and then back into the reservoir 34. During the time that the mercury droplets are in contact with the conductive portion of the rotor, any accumulated static charge is bled off. Mercury on the face 36 of the rotor disk 18 is similarly thrown outward and into the reservoir 34 by the spinning disk. It may be seen that the switch may operate in any position relative to the force of gravity.

The surface shape of the periphery 43 of therotor disk 18 is preferably a smooth flare or taper outward from the edge adjacent the spindle 2t toward the opposite edge adjacent the reservoir 34, best seen in Figure 3. The rotor disk 18 itself can either resemble a right section of a. cone, as shown in Figures 1 and 3, or the peripherai surface can be a right section of a hyperboloid or some other configuration so long as the diameters of the lamina of the disk increase as the center is moved along the axis toward the reservoir 34. The inner wall surface 28 of the commutator housing 16 is complementary to the.

surface of the periphery 48 'of the rotor 18 and close enough to keep the expelled mercury in contact with the rotor. The spacing interval used is determined by the nature of the conductive liquid, the materials making up the'rotor and the housing, and the spacing between adjacent contacts 26 on the inner wall 28.

The rotor and switch housing are preferably constructed of materials that are not readily wetted by mercury. The surface tension of the mercury then tends to keep it in. globules Which are more readily pumped .by the periphery to the reservoir. A model was constructed, in which the rotor. disk was made of steel, whichwas then used as a form for the inner surface of the housing. The

contact points and connecting wires were placed in a mold and the housing was cast from an. epoxy compound. After the epoxywhad set, the rotordisk-was removed, leaving an inner surface of a matching shape. A thin band of insulating material was then applied to the periphery of the disk, slightly wider than the circumferential area on the complementary inner wall surface which includes the contacts.

Turning now to Figure 2, a sectional view of the commutator taken along line 22 of Figure 1 and in the direction of the appended arrows, shows a disposition of contact points 26 around the inner wall 28 of the housing 16. Also, the rotor 18 is shown expelling a jet 50 of mercury 40 from the orifice 46. Each contact 26 is connected to a circuit, which may be either a source of signals, or to a signal receiving device. However, for multiple actuation of a single circuit during each revolution of the jet 50, several contacts may be electrically connected to the same external circuit. Each rotation of the rotor disk'16 and mercury jet 50 completes a connection between the common terminal and each of the circuits. w

In Figure 3, there is illustrated, in greater detail, a portion of the disk 18 and adjacent wall 26 of Figure 1. r In Figure 3, the jet 50 of mercury 40 may be seen at the contact 26. An extremely thin, non-conductive band 49 is shown on the periphery 48 adjacent the jet orifice 46.

Figure 4 is a detailed sectional view of a portion of an alternative design of a rotor disk 18' and a housing inner wall 28' adjacent thereto. In the embodimenttof Figure 4, the periphery 48 of the rotor disk 13 is not a right conic section, but rather is in the nature of a taper ing curve of revolution. The non-conducting band 49" is affixed to the periphery 48' in the area of the contact pairs 26', 26". It may be shown that virtually any pe-' ripheral surface configuration can be used so long. as the. edge of the rotor face adjacent the reservoir 34 has a greater diameter than the edge of the opposite rotor face.

Preferably, the surface 28? is chosen for the angle of attack of the jet relative to the contacts. If the jet strikes the inner wall and the contacts at an angle less than 45 from the normal to the surface, there is a greater. tendency to splash and splatter toward adjacent contacts, than if the contact angle is greater than 45 from the normal. A contact path nearly tangential to the surface will produce the least amount of turbulence and ChSr turbance. r

In the embodiment of Figure 4, an alternative con-' figuration of pairs of contacts, is shown. One set of contacts 26' is connected to a first set of terminals 30". and a second set of contacts 26", are connected to a first set of terminals 30 and a second set ofcontacts 26", are: connected to a second set of terminals 30": The terrninals 30' and 30" are connected to an otherwise complete choice of dimensiommay be readily suited for high-speed switching of analog signals. Since the liquid is subjected to positive pumping action at all times, the switch maybe operated in any position.

What is claimed as new is:

'l. .In an omnipositional rotary jet switch for sequentiall dyirecting a conductive fluid jet at a plurality of con tacts for'electrically connecting a corresponding plurality of cir'cuits,-a combination for positively controlling the flow of conductive liquid throughout the switch, said combination comprising: a rotor member having a peripheral surface including a jet orifice; a housing having said contacts circumferentially disposed in an inner surface surrounding said rotor, said housing including a reservoir portioniand' centrifugalpumpingmeans operable in the region immediately adjacent said jet orifice in response to rotation ofsaid rotor for pumping fluid from said jet orifice to said reservoir portion.

2. In an .omnipositional rotary jet switch for sequentially directing a conductive fluid jet at a plurality of contacts for electrically connecting a corresponding plurality of circuits, a combination for positively controlling the flow of conductive liquid throughout the switch, said combination comprising:. a rotor member including a disk portionihaving a peripheral surfaceincluding a jet orifice; ahousing having said contacts circumferentially disposed in an inner surface surrounding said disk portion, said housing including a reservoir portion for holding conductive fluid;T bafile r'neansseparating said disk portion from said reservoir. portion; and centrifugal pumping means operablein the region immediately adjacent said jet orifice, saidjpu'mping means being responsive to rotation of, said rotorfor positively pumping fluid adjacent said' disk portion back to said reservoir portion.

I 3. Inan omnipositional rotary jet switch for'sequentially directing a conductive fluid jet at a plurality of circuit. When a mercury jet 50 strikes both contacts 26" and 26", a conductivebridge is formed, completing the electrical circuit. 7 i

In operation, as the rotor disk 18 rotates, the jet 50' sequentially completes each of the circuits and, as the jet passes the contact'pairs, the contact is broken and 1 the mercury is pumped back to the reservoir and static;

charge is neutralized" by the rotor. V ments, the configuration of the peripheral surface has .a pumpingefiect on the mercury .and the orientation of thehousing'with respect to gravity is unimportant. For high speed switching, or, more. frequent actuation of the circuits, a plurality 'of jets may be utilized, for instance, in the form of a cro'ss in which the orifices diametrically oppose each other. Althoughthis embodiment is not shown, it can be-freadily understood that in operation, each circuitis completed four times in each revolution of the rotor disk.

The rotary jet used as either a switch or commutator and by suitable switch-of the present invention may be As in other embodicontacts for ielectrically connecting a corresponding plurality- .of' circuits, a combination for positively controlling the flow of conductive. liquid throughout the switch, said combination comprising-La switch housing having a reservoir portion; a rotor having a periphery including a jet'orificetherein, the peripheral surface of said rotor having an outwar'd slant from said jet orifice toward said reservoir; means responsive to rotation of said rotor for pumping conductive fluid to said jet orifice; an inner: surface in said housing surrounding said rotor closely adjacent said peripheral surface for retaining ejected jet fluid in contact with said peripheral surface; and said. peripheral surface and said inner surface cooperating for centrifugally pumping expelled jet fluid from said jet orifice to said reservoir in response to rotation of said rotor surface, whereby liquid is pumped from said reservoir to said jet and ,centrifugally pumped back to said reservoir, all in response to rotation of said rotor;

'4. In-an omnipositional rotary jet switch for sequentially directing a conductive fluid jet at a plurality of contacts for electrically connecting a corresponding plurality of circuits, a combination for positively controlling the flow of conductive'liquid throughout the switch, said combination comprising: a switch housing having a res-' surface cooperating for centrifugally pumping expelled jet fluid from said jet orifice to said reservoir in response to rotation of said rotor surface, whereby liquid is pumped from saidreservoir to said jet directed at said plurality of contacts in said inner surface,.and centrif- A spasm ugally pumped back to said reservoir, all in response to rotation of said rotor.

5. In an omnipositional rotary jet switch for sequentially directing a conductive fluid jet at a plurality of contacts for electrically connecting a corresponding plurality of circuits, a combination for positivelycontrolling the flow of conductive liquid throughout the switch, said combination comprising: a switch housing having a reservoir portion; a rotor having a periphery including a jet orifice therein, the peripheral surface of said rotor having an outward slant from said jet orifice toward said reservoir; baffie means interposed between said rotor and said reservoir for preventing viscous drag on said rotor; means responsive to rotation of said rotor for pumping conductive fluid to said jet orifice to form a fluid jet; an inner surface in said housing containing said plurality of contacts surrounding said rotor, said peripheral surface being spaced closely adjacent said inner surface for retaining ejected jet fluid in contact with said peripheral surface; said peripheral surface and said inner surface cooperating for centrifugally pumping expelled jet fluid from said jet orifice to said reservoir in response to rotation of said rotor surface, said rotor and said baffle means cooperating for centrifugally pumping fluid trapped therebetween into said reservoir in response to rotation of said rotor, whereby fluid is centrifugally pumped to said reservoir in response to rotation of said rotor.

6. In an omnipositional rotary jet commutator for sequentially directing an electrically conductive liquid jet at a plurality of contactsv for electrically connecting a corresponding plurality of circuits to a single circuit, a combination for positively controlling the flow of conductive liquid throughout said commutator, said combination comprising: a rotor member having a peripheral surface containing a jet orifice; a housing having said plurality of contacts circumferentially arrayed therein surrounding said rotor and including a reservoir portion; first centrifugal pumping means operable for positively pumping fluid from said reservoir to said jet orifice for forming a liquid jet; and second centrifugal pumping means operable in the region immediately adjacent said jet orifice for positively pumping expelled fluid from said jet orifice to said reservoir portion, said rotor being responsive to rotation for sequentially directing the jet formed by said first pumping means at each one of said plurality of contacts.

7. In an omnipositional rotary jet commutator for sequentially directing an electrically conductive liquid jet at a plurality of contacts for electrically connecting a corresponding pluralityof circuits to a single circuit, a combination for positively controlling the flow of conductive liquid throughout said commutator, said combination comprising: a rotor member having a peripheral surface containing a jet orifice; a housing having said plurality of contacts circumferentially arrayed therein sur rounding said rotor and including a reservoir portion; first centrifugal pumping means operable for positively pumping fluid from said reservoir to said jet orifice for forming a liquid jet; said rotor being responsive torotation for sequentially directing the jet formed by said first pumping means at each one of said plurality of contacts and second centrifugal pumping means for positively pumping fluid expelled from said jet orifice to said reservoirportion, said second pumping means including: a first surface coextensive with said peripheral surface, and having an outward slant from said jet orifice to said reservoir portion, a second surface interior to said housing, surrounding said first surface and having a matching outward slant in the direction of said reservoir portion, and rotor mounting means spacing said first surface in close proximity to said second surfacev for maintaining fluid between said surfaces in contact with said first surface and said second pumping means being. responsive to rotation of said rotor for positively pumping expelled jet fluid to said "reservoir from said jet orifice.

8., In an omnipositional rotary jet commutator for sequentially directing an electrically conductive liquid jet at a plurality of contacts for electrically connecting acorresponding plurality of circuits to a single curcuit, a combination for positively controlling the flow of conductive liquid throughout said commutator, said combination comprising: a rotor member having a peripheral surface containing a jet orifice; a housing having said plurality of contacts circumferentially arrayed therein surrounding said rotor and including a reservoir portion; first centrifugal pumping means operable for positively pumping fluid from said reservoir to said jet orifice for forming a liquid jet; said rotor being responsive to rotation for se quentially directing the jet formed by saidfirst pumping means at each one of said plurality of contacts; and second centrifugal pumping means for positively pumping fluid expelled from said jet orifice to said reservoir portion, said second pumping means including: a first surface coextensive with said peripheral surface and having an outward slantfrom a: first edge of said peripheral surface to a second edge of said peripheral surface in the direction of said reservoir, said jet orifice being located intermediate said first and second edges, a second surface interior to said housing surrounding said first surface having a matching outward slant in the direction of said reservoir portion and having said plurality of contacts circumferentially arrayedin the locus of said jet, and rotor mounting means spacing said first surface in close proximity to said second surface for maintaining fluid between said surfaces, in contact with said first surface, said second pumping means being responsive to rotation of said rotor for centrifugally pumping fluid expelled from said jet orifice to said reservoir, whereby expelled fluid splashed away from said reservoir is centrifugally pumped back to said reservoir. H

9. In an omnipositionalrotary jet switch for sequentially directing a jet of a conductive fluid at a plurality of contacts for electrically contacting a corresponding plurality of circuits, a combination for positively controlling the flow of conductive liquid through the switch, said combination comprising: a switch housing; a reservoir in said housing for storing conductive fluid; a rotor including a peripheral surface having a jet orifice therein, said peripheral surface of said rotor having an outward slant from said jet orifice toward a reservoir; an inner surface surrounding said rotor for circumferentially arraying said plurality of contacts closely adjacent to said peripheral surface, said rotor being spaced from said inner surface at a distance such that ejected jet fluid is retained in contact with said peripheral surface; baffle means interposed between said rotor and said reservoir for preventing viscous drag due to fluid in said'reservoir; first means internal to said rotor for pumping conductive fluid from said reservoir to said jet orifice in response to rotation of said rotor to form a jet; said peripheral surface and said inner surface being operable in combination for continually exerting a positive pumping action upon fluid ejected from said jet orifice for centrifugally pumping said fluid from said jet orifice to said reservoir, said rotor and said baflie means cooperating for pumping fluid trapped therebetween to said reservoir, said rotor directing said jet at said contacts, all in response to rotation of said rotor.

10. In an omnipositional rotary jet switch for sequentially directing a fluid jet at a plurality of contacts, a combination for positively controlling the flow of fluid throughout the switch, said combination comprising: a housing including, a reservoir portion for storage of conductive fluid, saidhousing including an inner surface with an inward taper, said plurality of contacts being peripherally arrayed about said inner surface; means conmeeting each of said contacts, said disk portion having a peripheral taper matching that of said inner surface; a jet orifice in the periphery of said disk portion, aligned with said plurality of contacts; fluid transport means internal to said rotor including pumping means for positively conveying conductive fluid from said reservoir portion to said jet orifice; and means imparting rotary motion to said rotor for forcefully expelling a fluid jet from said orifice, and for sequentially directing said jet at said plurality of contacts for electrically contacting each of said circuits, said matching surfaces of said rotor and inner surface being operable in response to rotational motion of said rotor for positively pumping expelled jet fluid from between said surfaces, back into said reservoir portion.

11. In an omnipositional rotary jet switch for sequentially contacting a plurality of circuits, the combination comprising: a rotor member having a peripheral surface containing a jet orifice; a housing surrounding said rotor and including a reservoir portion for storing conductive fluid; and means for positively controlling the flow of conductive fluid throughout the switch operable in response to rotation of said rotor, said means including first centrifugal pumping means operable for pumping fluid from said reservoir to said jet orifice and second centrifugal pumping means operable in the region immediately adjacent said jet orifice for positively pumping expelled fluid from said jet orifice to said reservoir portion, said second pumping means being further operable for discharging static electrical charge buildup in said expelled fluid.

' 12. In an omnipositional rotary jet switch for sequentially contacting a plurality of circuits, the combination comprising: a rotor member having a peripheral surface containing a jet orifice; a housing surrounding said rotor and including a reservoir portion for storing conductive fluid; and means for positively controlling the flow of conductive fluid throughout the switch operable in response to rotation of said rotor, said means including first centrifugal pumping means operable for pumping fluid from said reservoir to said jet orifice, second centrifugal pumping means for positively pumping expelled fluid from said jet orifice to said reservoir portion, said second pumping means being further operable for discharging static electrical charge buildup in said expelled fluid, and means to prevent electrical connection be tween said plurality of circuits and said electrically conductive rotor, said means comprising a band of electn'cally non-conductive material surrounding a portion of said peripheral surface including said jet orifice, said b-and electrically insulating said rotor from the immediately adjacent surface of said housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,066,575 Ralph Jan. 5, 1937 2,609,461 Holcomb et al Sept. 2, 1952 2,791,650 Gootherts May 7, 1957 

